Full colored photographs can contain millions of color values. However, the 8-bit GIF and certain other image formats can show only a limited number of colors. Dithering is the process through which the color range of a photo is reduced to 256 (or fewer) colors. In Dithering, pixels of two different colors are juxtaposed in such a way that it creates the illusion of a third color. It’s a very useful technique used by a variety of image formats to approximate unsupported colors.